In October, after a Chicago youth was brutally murdered, Rev. Jesse Jackson penned an opinion piece in the Chicago Sun Times in which he called for federal “civil rights intervention” in the Windy City. The beating death of 16-year-old Derrion Albert and other youth violence, Jackson declared, was a result of “systematic injustice” in Chicagos poorer neighborhoods attributable at least in part, according to Jackson, to everything from predatory lending schemes aimed at poor residents to the fact that not enough federal stimulus money was earmarked for minority businesses.

Jacksons op-ed was an extreme example of a sort of thinking that has predominated for decades, everywhere from criminologist circles to the media commentariat. Its a view of crime which holds that economic decline is at the root cause of growing social disorder. Its why as soon as our economy turned down late in 2008, predictions of a national surge in crime emerged. As one newspaper put it last January: “The crumbling economy is likely to spark growth in at least one arena during the new year: the national crime rate.”

But instead, the opposite has happened. Amidst what some would describe as the nations worst economic year in decades, violent crime has declined nationwide, part of a long trend, and seems to have fallen sharpest in places that bore the brunt of the recession. In New York City, where the financial sectors meltdown has rippled through the city, violent crime declined more than 10 percent for 2009. Moreover, those crimes that might be most attributable to economic circumstances, like robbery and grand larceny, fell the most in Gotham. Throughout California, a state hard hit by the housing markets meltdown, crime has plummeted. In the nations second largest city, Los Angeles, everything from murder (down 17 percent) to property crime declined, including a sharp drop in stolen cars (down nearly 20 percent). Nearby San Diego reported a 17 percent crime decline for the year-to-date.

These numbers arent shocking if you get beyond the conventional wisdom that people rob and steal when economic fortunes are declining. In fact, the opposite has often happened. Americas crime rate, for instance, spiked sharply in the mid-1960s, a time of economic prosperity and declining poverty, and continued its upward march through the remainder of that decade and into the economically difficult 1970s, before moderating during the steep recession of the early 1980s and then spiking again in 1985, a time of economic revival. Then crime rates began to decline in some places in the early 1990s, while the country struggled with the hangover from recession and the Gulf War. In many places crime has declined somewhat steadily since then.

Faced with these unexpected patterns, some experts have suggested that when it comes to crime and the economy, the exact opposite of the conventional wisdom may hold true: That is, it may well be that rising crime sparks economic decline, not visa versa, and that successful efforts to get law-breaking under control enhance economic opportunity. New York Citys experience certainly suggests that.

Like many American cities, New York found itself in the grip of a crack-cocaine epidemic in the mid-1980s that produced widespread violence and turned some neighborhoods into no-go zones where developers, residents and businesses feared to tread. As a result, even while Wall Street boomed and billions of dollars of new development poured into parts of the city, whole neighborhoods like the South Bronx and Bushwick, Brooklyn, continued to decay as investors bypassed these dangerous places.

Then in 1990 Gothams transit system hired Boston police veteran William Bratton, who instituted new methods of policing aimed at getting repeat offenders off the streets and restoring a sense of order to the subways. Bratton was influenced by the work of noted American political scientist James Q. Wilson and criminologist George Kelling, co-authors of a 1982 article in the Atlantic Monthly, “Broken Windows,” which argued that regular police patrols and community efforts to establish a sense of order in high crime areas discouraged criminal activity. Bratton moved to restore order in the subways by having his cops enforce even minor laws, like fare beating, a crime that was being ignored by many. Sure enough, major crimes declined because as it turned out that those who broke what some people considered insignificant laws were also most responsible for major crimes.

If there was one overarching message in Brattons success, it was that cops mattered. This was no small point because many cops had grown cynical after decades of hearing that it was economic conditions that drove crime and that the police were largely powerless to make a difference.

Brattons success landed him the job of police commissioner for New York under new mayor Rudy Giuliani, where he combined data-driven policing methods developed by the department with his broken windows ideas, sparking a sharp decline in crime that has continued through three successive police commissioners. Overall, crime is now down a startling 76 percent from its peak in New York, including a more than three-quarters decline in murders, which now stand at their lowest level since the city began keeping accurate records in the early 1960s.

Meanwhile, the turn down that began in the early 1990s has now unlocked development in whole neighborhoods of the city, sparking widespread economic revitalizations in places like the South Bronx, where Howard Cosell once famously summed up the disorder of the city during a Yankee Stadium World Series broadcast when he observed that, “Ladies and gentleman, the Bronx is burning.”

Bratton moved on to Los Angeles in 2002, where he led a 7-year decline in that citys crime rate. Other cities, ranging from Denver to Baltimore to troubled small cities like East Orange, N.J., learned the lessons of the policing revolution too, and the result has been a continuing decline in crime in many places.

We still dont know precisely what causes crime to rise, though there are any number of possible causes, from family breakdown (especially the rise in fatherless families) to a general decline in shared standards of order starting in the mid-1960s (what Daniel Patrick Moynihan once described as “defining deviancy down”). But if there is one thing that the revolution sparked by the ideas of Wilson and Kelling and the practice of Bratton has taught us, it is that police and policing matter, and that society is not powerless in the face of crime.

As those of us who have lived through cycles of rising crime and declining economic fortunes can attest, America would have been a different place, a far uglier and more distressing place in 2009 if in fact crime had spiked amidst our economic woe. That it didnt is a reason to be optimistic about our fortunes in the coming year.